how much percent of bypass level would be the real bypass when you use PODxt family as an effects processor unit? (turning off the amp models)

I've been wondering this question for years as a POD xt family user...

when you want to use PODxt as effects unit so as fx loop in an amp or while using other sources, since line6 has one of the most outstanding effects collection quality, you turn off the amp models and then you have the option of a bypass level control which is always factory preset in 78%... so I've been wondering if this is the equivalent to the truebypass level simulation (since Line6 PODxt are NOT true-bypass units)

I really would like to know if there is a universal percent level of bypass as a real bypass so I can use PODxt family(I have them all) not only as an effect unit but sometimes I want to use the input connecting a guitar, then use my choice of effect chains so I can run the PODxt output into the preamp or input's amp or any recording system's input (balanced or unbalanced)

I need to know this information because I don't want the level bypass be lack of level or exceded so I can use it in the way I describe

I know many of you would say or suggest me to play it until it clips, but I'm MORE than sure that Line6 has this knowledge for certain orientation

thank you very much if you have experienced this question and has got answers and solutions